The present invention relates to electronic devices with at least two cases attached openably to a base case on which a plurality of keys are provided.
Conventionally, for example, an electronic wristwatch is proposed in which an upper case is attached openably to a lower case with many key input units on an upper surface of the lower case and a display device provided on a lower surface of the upper case to optically display thereon data keyed in by a key input switch unit in order to add to the watch various functions such as a computer function and a data bank function in addition to a time display function, as disclosed in U.S. Pat. No. 4,985,878. Such an electronic wristwatch is capable of displaying the time as well as keyed-in data although it is miniaturized and has high portability.
The shape of the display elements of the display device and the number of keys required by the respective functions vary with function. For example, if such a device displays only numerical data such as that required by the time display and alarm time functions, the display device is required to have only numerical display elements comprising seven segments disposed in the form of 8. However, if alphabets are required to be displayed as in the data bank function, the display device is required to have a plurality of character display elements, for example, Of a 5.times.5 matrix. In addition, a diagram such as a graph is required to be displayed, the display device is required to have a matrix of many dot display elements disposed all over the display plane thereof. If numerical display elements or character display elements are to be provided, the number of figures for data to be displayed varies with function, so that the number of display elements required to be provided on the display device varies with function.
The number of keys required for control of various functions varies with function. If many keys are required, they are individually required to be miniaturized. If the number of keys is small, the size of each key may be increased so as to achieve improved operability.
However, the display device in the electronic wristwatch disclosed in the aforementioned U.S. Pat. No. 4,985,878 must be constructed so as to be able to display data on all the functions. The key-in switch unit must be constructed so as to be able to control all the functions. Thus, numerical or character display on the display device may be miniaturized or take a strange shape depending on function. All the functions must be controlled using small keys, so that key's operability is low.
If multi-function data is selected and displayed on a selected display, the keying operation is troublesome as well as likely to be mistaken because a function is selected by a small external key.